Specifically, the firm said that it used Distributed Denial of Service (DDoS) attacks, where a website is bombarded by requests for pages, effectively taking it offline.

The anonymous activists chose to use the same method to take Aiplex and the other organisations offline.

"We brought them down the same way they brought down The Pirate Bay, with a distributed denial of service," the group said in message posted on the web.

"They hired aiplex.com, who has been taken care of as well. They struck first, we struck harder."

The group has advised members to download software to help flood servers and has reportedly used botnets - networks of computers infected with malicious software and under the control of a hacker or criminal - to flood the websites.

A spokesperson for Aiplex confirmed the action to BBC News.

"Our site was under attack for some time," he said, adding its site had been taken offline for "about a day and half" over the weekend.

The MPAA has also confirmed the attack and said that it had "taken measures" to mitigate the effects.

All of the targeted sites are currently back online, but a message posted on the web suggests that the BPI will be targeted next.

"How do you stop the collective man power of an entire internet community? You can seize equipment, hunt down the originators of the attack, but this is a group who has prided themselves in remaining anonymous, and have done so very well through the power of the internet."

A similar anonymous group - also reportedly coordinated through 4chan - temporarily blocked access to key Australian government websites plans in protests against plans to introduce net filters in the country, earlier this year.